A plunger for reducing impact of a detent when liquid accumulation slides and falls and a method of use

Abstract

The present application relates to the technical field of oil and gas reservoir drainage gas recovery, and particularly relates to a plunger for reducing impact of a carding device when accumulated liquid slides and falls, and a use method, aiming to solve the problems of accumulated liquid sliding and impacting the carding device when the plunger is used for gas lifting and drainage, which leads to reduced gas lifting effect and frequent damage of the carding device. The plunger comprises a center pipe, a piston, upper supporting pieces and lower supporting pieces. A buffer cavity is arranged in the center pipe, and a vent hole is arranged on the side wall of the center pipe and communicates with the buffer cavity. The upper supporting pieces and the lower supporting pieces are annularly and evenly arranged and spaced apart around the center pipe. The piston opens the vent hole and drives the lower supporting pieces to push the upper supporting pieces after moving upward. The piston closes the vent hole and drives the lower supporting pieces to move after moving downward. The relative distance between the plunger and the inner wall of the production pipe string is optimally matched through the relative movement of the upper supporting pieces and the lower supporting pieces, accumulated liquid sliding is reduced, the center pipe is closed during the falling process, gas is stored in the center pipe to reduce the relative density and the falling speed of the plunger, and the impact is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil and gas reservoir drainage gas recovery, and particularly relates to a plunger for reducing impact of a locking device when accumulated liquid sliding and falling is prevented and a use method. BACKGROUND

[0002] The plunger gas lift drainage gas recovery process is one of main processes for stable production of a gas well. The plunger currently used has a large gap with a production string, and obvious accumulated liquid sliding phenomenon exists in the accumulated liquid lifting process, which leads to reduced gas lift effect. Meanwhile, the plunger has high speed and large impact force in the falling process, which often leads to damage of the locking device, and frequent replacement of the locking device is required, thereby affecting production efficiency. SUMMARY

[0003] The present application aims to provide a plunger for reducing impact of a locking device when accumulated liquid sliding and falling is prevented and a use method, so as to solve the problems of accumulated liquid sliding and impact of the locking device when the plunger gas lift drainage is performed, and reduced gas lift effect and frequent damage of the locking device.

[0004] In order to solve the above technical problems, the technical scheme provided by the present application is as follows:

[0005] A plunger for reducing impact of a locking device when accumulated liquid sliding and falling is prevented, comprising a central pipe, a piston, an upper supporting piece and a lower supporting piece; the central pipe is internally provided with a buffer cavity, and a vent hole is formed in the side wall of the central pipe and communicates with the buffer cavity; the piston is sleeved on the central pipe and is in sliding connection with the central pipe; the lower supporting piece is connected with the piston, and the upper supporting piece is connected with the central pipe; the plurality of upper supporting pieces and lower supporting pieces are annularly and uniformly arranged and spaced apart around the central pipe; the piston is moved upward to open the vent hole and drive the lower supporting piece to push the upper supporting piece, so that the upper supporting piece is moved away from the central pipe; and the piston is moved downward to close the vent hole and drive the lower supporting piece to move, so that the upper supporting piece is moved to be close to the central pipe.

[0006] Further, the plunger for reducing impact of a locking device when accumulated liquid sliding and falling is prevented further comprises a connecting sleeve, the connecting sleeve is connected with the central pipe and sleeved on the piston; the connecting sleeve is in contact with the upper supporting piece, and the contact surface is an inclined surface.

[0007] Further, the plunger for reducing impact of a locking device when accumulated liquid sliding and falling is prevented further comprises a limiting pin, the limiting pin is inserted into the upper supporting piece and connected with the connecting sleeve; the upper supporting piece is provided with a long hole, and the limiting pin is inserted into the long hole and can slide along the long hole.

[0008] Further, the plunger for reducing impact of a locking device when accumulated liquid sliding and falling is prevented further comprises a linkage clasp, the linkage clasp is sleeved on the connecting sleeve, and the upper supporting piece and the lower supporting piece are both connected with the linkage clasp.

[0009] Further, the upper supporting piece and the lower supporting piece are provided with linkage grooves, and a linkage clasp is inserted into the linkage grooves and can move along the axis of the central pipe relative to the linkage grooves.

[0010] Further, the plunger for reducing the impact of the clamping device when the accumulated liquid slides and falls back comprises a one-way valve set, which is sleeved on the central pipe and connected with the central pipe, and is inserted into the connecting sleeve and connected with the connecting sleeve; the piston is inserted into the annular space formed by the central pipe and the connecting sleeve, so as to form an inflation chamber together with the central pipe, the connecting sleeve and the one-way valve set.

[0011] Further, the one-way valve set comprises a valve seat, a valve core, a spring and a support seat; the valve seat is sleeved on the central pipe and connected with the central pipe, and is inserted into the connecting sleeve and connected with the connecting sleeve; the valve seat is provided with an inflation hole, the valve core and the spring are arranged in the inflation hole, and the support seat is inserted into the valve seat; one end of the spring is connected with the support seat, and the other end is connected with the valve core, which is configured to apply a pushing force to the valve core to block the inflation hole.

[0012] Further, the plunger for reducing the impact of the clamping device when the accumulated liquid slides and falls back back further comprises a limiting ring, which is sleeved on the central pipe and arranged between the one-way valve set and the piston.

[0013] Further, the plunger for reducing the impact of the clamping device when the accumulated liquid slides and falls back back further comprises a pressing cap, which is inserted into the central pipe and connected with the central pipe to close the buffer chamber.

[0014] Another aspect of the present application provides a use method of the plunger for reducing the impact of the clamping device when the accumulated liquid slides and falls back, which adopts the above-mentioned plunger for reducing the impact of the clamping device when the accumulated liquid slides and falls back, and comprises the following steps:

[0015] Lifting: during the lifting process, the piston moves upward to drive the lower supporting piece, so that the lower supporting piece pushes the upper supporting piece away from the central pipe, thereby reducing the gap between the upper supporting piece and the inner wall of the production pipe string;

[0016] Falling back: during the falling back process, the piston moves downward to close the vent hole, and at the same time drives the lower supporting piece to move downward to make the upper supporting piece close to the central pipe.

[0017] The technical effects that can be achieved by the present application in combination with the above technical solutions are as follows:

[0018] The plunger for reducing impact of the locking device when the accumulated liquid slips and falls comprises a center tube, a piston, an upper supporting sheet and a lower supporting sheet; the center tube is internally provided with a buffer cavity, and a vent hole is formed in the sidewall of the center tube and communicates with the buffer cavity; the piston is sleeved on the center tube and is in sliding connection with the center tube; the lower supporting sheet is connected with the piston, and the upper supporting sheet is connected with the center tube; a plurality of upper supporting sheets and lower supporting sheets are annularly and uniformly distributed and are arranged at intervals around the center tube; the piston is moved upward to open the vent hole and drive the lower supporting sheet to push the upper supporting sheet, so that the upper supporting sheet is moved away from the center tube; and the piston is moved downward to close the vent hole and drive the lower supporting sheet to move, so that the upper supporting sheet is moved to be close to the center tube.

[0019] The plunger for reducing impact of the locking device when the accumulated liquid slips and falls comprises a center tube, a piston, an upper supporting sheet and a lower supporting sheet; the center tube is internally provided with a buffer cavity, and a vent hole is formed in the sidewall of the center tube and communicates with the buffer cavity; the piston is sleeved on the center tube and is in sliding connection with the center tube; the lower supporting sheet is connected with the piston, and the upper supporting sheet is connected with the center tube; a plurality of upper supporting sheets and lower supporting sheets are annularly and uniformly distributed and are arranged at intervals around the center tube; the piston is moved upward to open the vent hole and drive the lower supporting sheet to push the upper supporting sheet, so that the upper supporting sheet is moved away from the center tube; and the piston is moved downward to close the vent hole and drive the lower supporting sheet to move, so that the upper supporting sheet is moved to be close to the center tube.

[0020] Meanwhile, the upper supporting sheet is retracted when the plunger is moved downward, so that the wear of the upper supporting sheet by the production pipe string is reduced, and the service life of the plunger is improved.

[0021] In addition, as the piston is moved upward, the vent hole is in an open state, at this time, the buffer cavity in the center tube can enter part of the liquid, so that the plunger maintains the original density, the liquid carrying capacity is prevented from being reduced due to the too fast upward movement of the plunger, and the lifting effect is ensured. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings needed to be used in the specific embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0023] Figure 1 The structure schematic diagram of the plunger for reducing impact of the locking device when the accumulated liquid slips and falls in a lifting state is provided for the embodiments of the present application.

[0024] Figure 2 The structure schematic diagram of the plunger for reducing impact of the locking device when the accumulated liquid slips and falls in a lifting and falling state is provided for the embodiments of the present application.

[0025] Figure 3 The structure schematic diagram of the upper supporting sheet is provided.

[0026] Figure 4 is a schematic view of the structure of the upper holder plate;

[0027] Figure 5 is a schematic view of the structure of the upper holder plate and the lower holder plate in the falling-back state;

[0028] Figure 6 is a schematic view of the structure of the upper holder plate and the lower holder plate in the falling-back state;

[0029] Figure 7 is a schematic view of the structure of the upper holder plate and the lower holder plate in the lifting state;

[0030] Figure 8 is a schematic view of the structure of the upper holder plate and the lower holder plate in the lifting state.

[0031] Icon: 100 - central pipe; 200 - piston; 300 - upper holder plate; 400 - lower holder plate; 500 - connecting sleeve; 600 - limiting pin; 700 - linkage snap ring; 800 - one-way valve group; 900 - limiting ring; 1000 - pressing cap; 1100 - fixing pin; 410 - flange; 810 - valve seat; 820 - valve core; 830 - spring; 840 - support seat; a - buffer cavity; b - air hole; c - long hole; d - linkage groove; e - inflation cavity; f - inflation hole. DETAILED DESCRIPTION

[0032] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. The components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0033] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative labor are within the scope of protection of the present application.

[0034] Some embodiments of the present application will be described in detail below with reference to the accompanying drawings. The following embodiments and features in the embodiments can be combined with each other without conflict.

[0035] The currently used plunger has a large gap with the production string, and there is a significant accumulation of liquid slipping phenomenon in the lifting process of the accumulated liquid, which reduces the gas lifting effect. At the same time, the plunger has a high speed and a large impact force in the falling-back process, which often causes damage to the locking device, and frequent replacement of the locking device is required, which affects the production efficiency.

[0036] In view of this, the present invention provides a plunger for reducing the impact of the locking device when the liquid accumulates and slips back, comprising a central tube 100, a piston 200, an upper support plate 300, and a lower support plate 400; the central tube 100 has a buffer chamber a inside, and a vent hole b communicating with the buffer chamber a is opened on the side wall; the piston 200 is fitted onto the central tube 100 and slidably connected to the central tube 100; the lower support plate 400 is connected to the piston 200, and the upper support plate 300 is connected to the central tube 100; multiple upper support plates 300 and lower support plates 400 are evenly distributed in a ring around the central tube 100 and spaced apart; after the piston 200 moves upward, it opens the vent hole b and drives the lower support plate 400 to push the upper support plate 300, so that the upper support plate 300 moves away from the central tube 100; after the piston 200 moves downward, it closes the vent hole b and drives the lower support plate 400 to move the upper support plate 300 closer to the central tube 100.

[0037] The plunger provided by this invention, which reduces the impact on the locking device during liquid accumulation and slippage, is formed by an annularly distributed and spaced upper support plate 300 and lower support plate 400 forming a sealing ring. The upper support plate 300 in the sealing ring can be displaced radially along the sealing ring. When the plunger moves upward and requires improved sealing performance, the upper support plate 300 moves away from the center of the sealing ring to reduce the gap between the sealing ring and the inner wall of the production tubing, achieving optimal fit with the production tubing and reducing liquid accumulation and slippage during the lifting process. When the plunger moves downward, the piston 200 closes the vent hole b, and the buffer chamber a is filled with gas to reduce the relative density of the plunger and decrease the fall speed, thereby reducing the impact caused by the plunger's fall and reducing damage to the locking device.

[0038] At the same time, when the plunger moves down, the upper support plate 300 retracts, which can reduce the wear of the upper support plate 300 on the production tubing and improve the service life of the plunger.

[0039] In addition, as the piston 200 moves upward, the vent hole b is in the open state. At this time, some liquid can enter the buffer chamber a in the central tube 100, so that the plunger maintains its original density, avoids the plunger rising too fast and thus reduces the liquid carrying capacity, and ensures the lifting effect.

[0040] The following combination Figures 1-8 The structure and shape of the plunger used to reduce the impact of the locking device when the anti-liquid slippage and fall back as provided in this embodiment are described in detail:

[0041] In the optional solution provided in this embodiment, the plunger that reduces the impact on the locking device when the accumulated liquid slips and falls back also includes a connecting sleeve 500 and a one-way valve assembly 800. For example... Figure 1As shown, the one-way valve set 800 is sleeved on the central pipe 100 and connected with the central pipe 100, and the one-way valve set 800 is inserted into the connecting sleeve 500 and connected with the connecting sleeve 500; the connecting sleeve 500 is sleeved on the piston 200, and the connecting sleeve 500 is in contact with the upper supporting piece 300, and the contact surface is an inclined surface; when the upper supporting piece 300 moves upward relative to the connecting sleeve 500, the inclined surface contact makes the upper supporting piece 300 away from the central pipe 100 to shorten the distance from the inner wall of the production string, thereby reducing the sliding of the accumulated liquid.

[0042] In this embodiment, the one-way valve set 800 includes a valve seat 810, a valve core 820, a spring 830 and a support seat 840. Specifically, as shown in Figure 1 As shown, the valve seat 810 is sleeved on the central pipe 100 and connected with the central pipe 100 in a threaded manner, and the valve seat 810 is inserted into the connecting sleeve 500 and connected with the connecting sleeve 500 in a threaded manner; the valve seat 810 is provided with an inflation hole f, the valve core 820 and the spring 830 are arranged in the inflation hole f, and the support seat 840 is inserted into the valve seat 810; one end of the spring 830 is connected with the support seat 840, and the other end is connected with the valve core 820, which is configured to apply a pushing force to the valve core 820 to block the inflation hole f, thereby realizing one-way sealing. Wherein, the valve core 820 is provided as a ball, the inflation hole f is provided as a stepped hole, and the support seat 840 is inserted into the inflation hole f and connected with the inflation hole f in a threaded manner.

[0043] In this embodiment, the piston 200 is inserted into the annular space surrounded by the central pipe 100 and the connecting sleeve 500, thereby forming an inflation cavity e with the central pipe 100, the connecting sleeve 500 and the one-way valve set 800. The inflation hole f is in communication with the inflation cavity e to communicate with the inflation cavity e. When the inflation cavity e is inflated, the air pressure pushes the valve core 820 to compress the spring 830, so that the inflation hole f is opened.

[0044] In this embodiment, the two upper supporting pieces 300 and the two lower supporting pieces 400 are arranged in a ring shape and are arranged at intervals, as shown in Figure 5 、 Figure 6 As shown, the piston 200 has not moved up at this time, and the upper and lower ends of the plunger can be communicated through the gap between the upper supporting piece 300 and the inner wall of the production string and the gap between the two lower supporting pieces 400 at this time. When the plunger moves up, the piston 200 moves up relative to the central pipe 100 under the action of the bottom hole pressure and drives the lower supporting piece 400 to move up, as shown in Figure 7 、 Figure 8 As shown in Figure 4As shown, the lower supporting sheet 400 is provided with a flange 410, which abuts against the upper supporting sheet 300 to push the upper supporting sheet 300 upward, and then the upper supporting sheet 300 is moved away from the central pipe 100 under the action of the inclined surface of the connecting sleeve 500 to reduce the gap between the upper supporting sheet 300 and the inner wall of the production pipe string, thereby avoiding liquid slipping during the lifting process. In the embodiment, only the upper supporting sheet 300 moves in the radial direction of the central pipe 100 to ensure the sealing performance during the lifting process, reduce liquid slipping, and ensure a sufficient gap during the falling process to ensure normal falling.

[0045] In an optional solution of the embodiment, the plunger for reducing the impact of the clamping device during the anti-liquid-slipping falling process further comprises a limiting pin 600 and a linkage clasp 700. The limiting pin 600 is inserted into the upper supporting sheet 300 and connected with the connecting sleeve 500; the upper supporting sheet 300 is provided with a long hole c, and the limiting pin 600 is inserted into the long hole c and can slide along the long hole c, as shown. Figure 3 Specifically, the limiting pin 600 cooperates with the long hole c to limit the movement of the upper supporting sheet 300 in the radial direction of the central pipe 100, prevent the upper supporting sheet 300 from falling off, and avoid the circumferential movement of the upper supporting sheet 300, so that the upper supporting sheet 300 only moves in the radial and axial directions of the central pipe 100.

[0046] The linkage clasp 700 is sleeved on the connecting sleeve 500, and the upper supporting sheet 300 and the lower supporting sheet 400 are connected with the linkage clasp 700, as shown. Figure 3 、 Figure 4 As shown, the upper supporting sheet 300 and the lower supporting sheet 400 are both provided with a linkage groove d, and the linkage clasp 700 is inserted into the linkage groove d and can move relative to the linkage groove d along the axial direction of the central pipe 100. The lower supporting sheet 400 can drive the upper supporting sheet 300 to move downward through the linkage clasp 700 to ensure that the upper supporting sheet 300 moves toward the central pipe 100, thereby avoiding the upper supporting sheet 300 from being stuck and failing to retract.

[0047] In an optional solution of the embodiment, in order to move the upper supporting sheet 300 toward the central pipe 100, a return spring can be provided, which is sleeved on the limiting pin 600, one end of which is connected with the limiting pin 600, and the other end of which is connected with the upper supporting sheet 300, so as to apply a pushing force to the upper supporting sheet 300 to press the connecting sleeve 500. Thus, while the lower supporting sheet 400 drives the upper supporting sheet 300 to move downward, the upper supporting sheet 300 moves toward the central pipe 100 under the pushing of the return spring.

[0048] In an optional embodiment, the plunger that reduces the impact on the locking device when the anti-liquid slippage and fall back also includes a limiting ring 900, a pressure cap 1000, and a fixing pin 1100. The limiting ring 900 is fitted onto the central tube 100 and positioned between the one-way valve assembly 800 and the piston 200 to limit the upward movement distance of the piston 200; the pressure cap 1000 is inserted into the central tube 100 and threadedly connected to the central tube 100 to seal the buffer chamber a. The fixing pin 1100 is inserted into the lower support plate 400 and the piston 200 to fix the lower support plate 400 onto the piston 200.

[0049] In an optional embodiment, the connection between the lower support plate 400 and the piston 200 can refer to that of the upper support plate 300. Instead of using the fixing pin 1100, a limiting pin 600 is used, and an elongated hole c is formed in the lower support plate 400. A corresponding inclined surface is provided on the connecting sleeve 500 to allow the lower support plate 400 to move away from the central tube 100 during its upward movement. During the plunger's retraction, the lower support plate 400 can also retract to reduce friction between the lower support plate 400 and the inner wall of the production tube, further improving the plunger's service life. Similarly, a return spring can be provided to apply a pushing force to the lower support plate 400, causing it to press against the connecting sleeve 500.

[0050] Based on the plunger provided in this embodiment that reduces the impact on the locking device when preventing liquid accumulation and slippage, a method for using the plunger that reduces the impact on the locking device when preventing liquid accumulation and slippage is proposed, including the following steps:

[0051] Preparation: Based on the height of the liquid column in the well and the bottom hole pressure, nitrogen gas at a certain pressure is injected into the air chamber e through the air filling hole f, causing piston 200 to close the air vent b. Simultaneously, the lower support plate 400 moves downwards to ensure the upper support plate 300 is in the retracted state. Figure 2 As shown, the plunger is then inserted into the wellbore locking position.

[0052] Lifting: When the well is shut in, the combined action of the accumulated fluid in the well and the bottom hole pressure pushes the piston 200 upward. During this upward movement, the piston 200 drives the lower support plate 400 to move as well. When the flange 410 on the lower support plate 400 contacts the upper support plate 300, it drives the upper support plate 300 to move along the inclined surface of the connecting sleeve 500. When the piston 200 reaches the limit ring 900, the piston 200 stops moving. At this point, the upper support plate 300 and the lower support plate 400 interlock and, together with the inclined surface of the connecting sleeve 500, form a seal against the accumulated fluid in the upper part of the well. Figure 1 As shown. When drainage is required, the well is opened. Under the pressure at the bottom of the well, the plunger moves upward, carrying the accumulated fluid to the wellhead for drainage, thereby enabling gas production. It should be noted that the vent b is located at the lower part of the buffer chamber a. When the plunger reaches the wellhead, the liquid in the buffer chamber a can be discharged through the vent b, while gas can enter the buffer chamber a.

[0053] Fall back: the plunger is behind the wellhead, due to the reduction of the liquid column pressure and the well pressure, the piston 200 is reset under the thrust of the gas in the inflation chamber e, and the lower support plate 400 is also moved down during the downward movement of the piston 200, and the linkage clasp 700 is moved down during the downward movement of the lower support plate 400, and the upper support plate 300 is moved down through the linkage clasp 700, thereby achieving the reset of the piston 200, the lower support plate 400 and the upper support plate 300, at this time the upper support plate 300 is close to the central tube 100, and the distance between the upper support plate 300 and the inner wall of the production string is increased, which is beneficial to reduce the wear of the upper support plate 300 and ensure the smooth fall back of the plunger. The piston 200 seals the vent hole b when it is reset, and a certain amount of gas is stored in the central tube 100, as shown, thereby reducing the relative density of the plunger and slowing down the fall back speed of the plunger, which is beneficial to reduce the impact of the plunger on the locking device. Figure 2

[0054] Finally, it should be pointed out that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.​

Claims

1. A plunger for reducing impact of a detent when a fluid accumulation slips back and falls, characterized by, It comprises a center tube (100), a piston (200), an upper supporting sheet (300) and a lower supporting sheet (400); The center tube (100) is internally provided with a buffer cavity (a), and a ventilation hole (b) is formed in the side wall and communicates with the buffer cavity (a); The piston (200) is sleeved on the center tube (100) and is in sliding connection with the center tube (100); The lower supporting sheet (400) is connected with the piston (200), and the upper supporting sheet (300) is connected with the center tube (100); A plurality of the upper supporting sheets (300) and the lower supporting sheets (400) are annularly and uniformly distributed and spaced apart around the center tube (100); After the piston (200) moves upward, the ventilation hole (b) is opened, and the lower supporting sheet (400) is driven to push the upper supporting sheet (300), so that the upper supporting sheet (300) moves away from the center tube (100); After the piston (200) moves downward, the ventilation hole (b) is closed, and the lower supporting sheet (400) is driven to move, so that the upper supporting sheet (300) moves towards the center tube (100); It further comprises a connecting sleeve (500), which is connected with the center tube (100) and sleeved on the piston (200); The connecting sleeve (500) is in contact with the upper supporting sheet (300), and the contact surface is an inclined surface; It further comprises a limiting pin (600), which is inserted into the upper supporting sheet (300) and connected with the connecting sleeve (500); The upper supporting sheet (300) is provided with a long hole (c), and the limiting pin (600) is inserted into the long hole (c) and can slide along the long hole (c); It further comprises a linkage snap ring (700), which is sleeved on the connecting sleeve (500), and the upper supporting sheet (300) and the lower supporting sheet (400) are connected with the linkage snap ring (700); The upper supporting sheet (300) and the lower supporting sheet (400) are both provided with a linkage groove (d), and the linkage snap ring (700) is inserted into the linkage groove (d) and can relatively move along the axis direction of the center tube (100) and the linkage groove (d).

2. The plunger of claim 1, wherein, It further comprises a one-way valve group (800), which is sleeved on the center tube (100) and connected with the center tube (100), and is inserted into the connecting sleeve (500) and connected with the connecting sleeve (500); The piston (200) is inserted into the annular space surrounded by the center tube (100) and the connecting sleeve (500), so as to form an inflation cavity (e) together with the center tube (100), the connecting sleeve (500) and the one-way valve group (800).

3. The plunger of claim 2, wherein, The one-way valve group (800) comprises a valve seat (810), a valve core (820), a spring (830) and a support seat (840). The valve seat (810) is sleeved on and connected with the central pipe (100), the valve seat (810) is inserted into and connected with the connecting sleeve (500); The valve seat (810) is provided with an inflation hole (f), the valve core (820) and the spring (830) are arranged in the inflation hole (f), and the support seat (840) is inserted into the valve seat (810); One end of the spring (830) is connected with the support seat (840), and the other end is connected with the valve core (820), which is configured to apply a pushing force to the valve core (820) to block the inflation hole (f).

4. The plunger of claim 3, wherein, Further comprising a limiting ring (900), the limiting ring (900) is sleeved on the central pipe (100) and arranged between the one-way valve group (800) and the piston (200).

5. The plunger of claim 4, wherein, Further comprising a pressing cap (1000), the pressing cap (1000) is inserted into and connected with the central pipe (100) to close the buffer cavity (a).

6. A method of using the anti-accumulation and anti-slip back plunger for reducing the impact of the plunger on the latch during the falling back, using the anti-accumulation and anti-slip back plunger for reducing the impact of the plunger on the latch during the falling back according to any one of claims 1-5, characterized in that, The method comprises the following steps: Lifting: during the lifting process, the piston (200) moves upward to drive the lower supporting piece (400), so that the lower supporting piece (400) pushes the upper supporting piece (300) away from the central pipe (100), thereby reducing the gap between the upper supporting piece (300) and the inner wall of the production pipe string; Falling back: during the falling back process, the piston (200) moves downward to close the air hole (b), and at the same time drives the lower supporting piece (400) to move downward to make the upper supporting piece (300) close to the central pipe (100).

Images